GB2149773A - Refractory moulded bodies of zirconium dioxide - Google Patents
Refractory moulded bodies of zirconium dioxide Download PDFInfo
- Publication number
- GB2149773A GB2149773A GB08429023A GB8429023A GB2149773A GB 2149773 A GB2149773 A GB 2149773A GB 08429023 A GB08429023 A GB 08429023A GB 8429023 A GB8429023 A GB 8429023A GB 2149773 A GB2149773 A GB 2149773A
- Authority
- GB
- United Kingdom
- Prior art keywords
- weight
- mgo
- percent
- cao
- stabiliser
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/48—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zirconium or hafnium oxides, zirconates, zircon or hafnates
- C04B35/486—Fine ceramics
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Composite Materials (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Compositions Of Oxide Ceramics (AREA)
Abstract
A refractory moulded body comprises 94 to 97 percent by weight zirconium dioxide and is partially stabilised with 2 to 4 percent by weight CaO, MgO or Y2O3. The body contains 1 to 1.5 percent by weight SiO2 when stabilised only by CaO, and 0.8 to 1.5 percent by weight SiO2 when stabilised with MgO or Y2O3 or a mixture of CaO and MgO. The amount of stabiliser present is at least double that of SiO2 by weight.
Description
SPECIFICATION
Refractory moulded bodies of zirconium dioxide
This invention relates to refractory moulded bodies of zirconium dioxide of the type which are partially stabilised with 2 to 4 percent by weight CaO, MgO orY203 and may contain one or more of the impurities
SiO2, Al2O3, Felon and/or TiO2 as the remainder.
It is known to use zirconium dioxide materials for the manufacture of refractory moulded bodies. In this connection it is known that stabilisers in the form of calcium oxide, magnesium oxide, or Yttrium oxide can be added to the starting material so that the moulded bodies are less susceptible to cracks in the subsequent firing process which is effected at temperatures between 1600"C and 200000 as a result of their expansion characteristics and thus substantially maintain their strength. In "Stahl und Eisen" (Steel and Iron), Volume 97, 1977, pages 945-946, information is given about the thermal characteristics of partially stabilised zirconium dioxide in which magnesiumoxide and calcium oxide are referred to as stabilising additives.It is stated in this article that in the presence of oxidising impurities, primarily of silicon dioxide, a destabilisation can occur even at the melting temperature of steel. It is further stated therein that partially stabilised zirconium dioxide has a higher resistance to changes in temperature than homogeneous fully stabilised zirconium dioxide. In an article in "Interceram" No. 2, 1982, pages 126/129, there is also a report on the influence of impurities on the stabilisation of zirconium dioxide. The zirconium dioxide is stabilised with calcium oxide and for this purpose impurities such as SiO2, Al2O3, Fe2O3, Na2O, K2O or mixtures of SlO2 and
Al203 or of SiO2 and Na2O or K2O were added.If is however stated in this publication that it is only with a small addition of SiO2 at low temperatures that a considerable increase of the density is achieved without a pronounced destabilisation. There is also a report on the partial stabilisation of zirconium dioxide by adding calcium oxide or magnesium oxide in "Stahl und Eisen" (Steel and Iron), Volume 100, 1980, pages 1457-1462.
It is an object of the present invention to provide refractory moulded bodies based on partially stabilised zirconium dioxide of the type referred to which have an even better resistance to changes in temperature.
It has now been found that the resistance to changes in temperature of such refractory bodies can be substantially improved by precisely adjusting the proportions of the individual stabiliser and by providing a substantial proportion of silicon dioxide in the partial stabilisation in addition to the components CaO, MgO or Y203 which are present as a stabiliser.
According to the present invention a refractory moulded body of the type comprising 94 to 97 percent by weight zirconium oxide (ZrO2) and partially stabilised by a content of 2 to 4 percent by weight CaO, MgO or
Y203 as stabiliser is characterised in that the body contains only CaO as stabiliser and additionally 0.8 to 1.5 percent by weight SiO2 or MgO or Y203 or a mixture of CaO and MgO as stabiliser and additionally 0.8 to 1.5 percent by weight SiO2, the amount of stabiliser being at least double that of SiO2 by weight.
In one embodiment the body contains MgO as stabiliser and 1.0 to 1.2 percent by weight SiO2.
It is preferred that during the manufacture of the body its iron content, over and above the iron already contained in the zirconium dioxide, is adjusted by the addition of iron oxide whereby the iron content of the body is 0.6 to 0.8 percent by weight.
In-a further embodiment, a mixture of MgO and CaO is used as stabiliser, the ratio of MgO to CaO being between 1:2 and 2:1 by weight.
The invention will now be described in more detail with reference to the following Examples in which
Examples 1 to 5 are in accordance with the present invention and Example 6 which falls outside the invention.
A natural Baddeleyite with the following chemical analysis was used as the starting material:
ZrO2 SlO2 Al203 Ti02 Fe203 CaO
Zirconium Oxide 99.1 0.40 0.17 0.07 0.22 0.44
Fine grained SiO2 (finely ground quartz dust), CaO in the form of calcium zirconate (CaZrO3), MgO, Y203 and Fe2O3 were added to the Baddeleyite which had a grain size less than 0.063 mm. Using 2 percent by weight
Dextrin (dry) and 2 to 2.5 percent water as a bonding agent, the fine grained mixtures were homogenised in a mixer, pressed into moulded bodies at a pressing pressure of about 100 N/mm2, dried and subsequently fired at 2000 C. Table 1 (information in percent by weight) shows the composition of the mixtures for
Examples 1 to 5.The composition and the properties of the fired moulded bodies in accordance with the
Examples are shown in Table 2.
TABLE 1
1 2 3 4 5
Zirconium Oxide upto0.063mm 100 100 100 100 100
SiO2 +0.8 +0.8 +0.5 +0.8 It1.0 CaZrO3 +12.0 +6.5 MgO +2.5 +2.5 +2.0 Y203 +3.5 Fe2O3 +0.5 +0.5 +0.5 +0.5
TABLE 2
1 2 3 4 5 6
ZrO2 94.6 95.3 95.7 94.7 93.9 96.7 SlO2 1.20 1.15 0.88 1.17 1.48 0.42 At203 0.17 0.16 0.18 0.18 0.17 0.19
TiO2 0.06 0.06 0.07 0.08 0.07 0.08 Fe203 0.68 0.75 0.70 0.23 0.74 0.19
CaO 3.26 0.05 0.04 0.05 1.78 0.03
MgO 2.45 2.52 1.86 2.30
Y203 3.52
Bulk Den
sity g/cm3 4.75 4.95 4.90 4.93 4.91 4.76
E-Modulus
N/mm2 55000 36000 52000 42000 32000 90000
Resistance
to changes
in temperature
(water)
DIN 51068 > 30 > 30 > 30 > 30 > 30 10
Temperature Shock 1700 C NO CRACK FORMATION Cracks within
2 min.
Proportion
of Monoclinic ZrO2Wt.% 87 95 90 84 92 72
The refractory moulded bodies of Example 1 were partially stabilised with CaO, those of Examples 2 and 3 with MgO, those of Example 4 with Y203 and those of Example 5 with a mixture of MgO and CaO.SiO2 was in each case added as an additional component to the mixture. With the exception of Example 4 there was also an addition of Fe2O3.
The moulded bodies of Examples 1 to 5 have a very good resistance to changes in temperature which is apparent from the values for the E-modulus (calculated from the ultrasonic travel time the resistance to changes in temperature (determined in accordance with DIN 51068, part 1 Water Quenching Method), and by virtue of the behaviour with respect to temperature shock when using moulded bodies (extrusion nozzle with 60 mm external diameter) in a furnace operated at 1700"C. It was further determined that in the moulded bodies in accordance with the invention, a relatively high proportion of monoclinic Baddeleyite is present with respect to the proportion of stabiliser. By contrast, a moulded body in accordance with Example 6, which is outside the present invention, which was merely partially stabilised with the addition of MgO, reached a low resistance to changes in temperature whilst having a high E-Modulus and a low proportion of monoclinic zirconium oxide.
Claims (5)
1. A refractory moulded body comprising 94 to 97 percent by weight zirconium dioxide (ZrO2) and partially stabilised by a content of 2 to 4 percent by weight CaO, MgO or Y203 as stabiliser, characterised in that the body contains only CaO as stabiliser and additionally 1 to 1.5 percent by weight SiO2, or MgO or
Y203 or a mixture of CaO and MgO as stabiliser and additionally 0.8 to 1.5 percent by weight SiO2, the amount of stabiliser being at least double that of SlO2 by weight.
2. A body as claimed in Claim 1, which contains 1.0 to 1.2 percent by weight SiO2 and MgO as stabiliser.
3. A body as claimed in Claim 1 or 2, including an iron content of 0.6 to 0.8 percent by weight.
4. A body as claimed in Claim 1 or 3, containing a mixture of MgO and CaO as stabiliser, the ratio of MgO to CaO being between 1:2 and 2:1 by weight.
5. A refractory moulded body substantially as specifically herein described in any one of the accompanying Examples 1 to 5.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19833341524 DE3341524A1 (en) | 1983-11-17 | 1983-11-17 | FIRE-RESISTANT MOLDED BODY FROM PARTLY STABILIZED ZIRCONIUM DIOXIDE |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8429023D0 GB8429023D0 (en) | 1984-12-27 |
| GB2149773A true GB2149773A (en) | 1985-06-19 |
| GB2149773B GB2149773B (en) | 1987-02-04 |
Family
ID=6214526
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08429023A Expired GB2149773B (en) | 1983-11-17 | 1984-11-16 | Refractory moulded bodies of zirconium dioxide |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS60118669A (en) |
| DE (1) | DE3341524A1 (en) |
| GB (1) | GB2149773B (en) |
| IL (1) | IL73525A (en) |
| NL (1) | NL8403374A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4835123A (en) * | 1986-02-03 | 1989-05-30 | Didier-Werke Ag | Magnesia partially-stabilized zirconia |
| US4961835A (en) * | 1987-10-20 | 1990-10-09 | Murata Manufacturing Co., Ltd. | Solid electrolyte, sensor therewith and method of making said sensor |
| EP1118601A1 (en) * | 1998-06-22 | 2001-07-25 | Showa Denko Kabushiki Kaisha | Refractory for casting rare earth alloy and method for producing the same and method for casting rare earth alloy |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6291692A (en) * | 1985-10-16 | 1987-04-27 | Ngk Insulators Ltd | Magnet driving device for rotating apparatus |
| DE3803898A1 (en) * | 1988-02-09 | 1989-08-10 | Degussa | PRESSLINGS BASED ON PYROGEN-PRODUCED ZIRCONDIOXIDE, METHOD FOR THE PRODUCTION THEREOF AND THEIR USE |
| DE4003608C1 (en) * | 1990-02-07 | 1991-06-27 | Didier-Werke Ag, 6200 Wiesbaden, De | |
| JPH04357165A (en) * | 1991-05-29 | 1992-12-10 | Ngk Insulators Ltd | Zirconia porcelain and electrochemical element using the same |
| JP2760751B2 (en) * | 1994-06-13 | 1998-06-04 | 品川白煉瓦株式会社 | Immersion nozzle for continuous casting |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2937102A (en) * | 1957-03-18 | 1960-05-17 | Zirconium Corp Of America | Zirconia stabilization control |
| US3518100A (en) * | 1967-10-30 | 1970-06-30 | Dresser Ind | Stabilized zirconia shapes |
| DE2714558A1 (en) * | 1977-04-01 | 1978-10-12 | Bosch Gmbh Robert | SINTER-ACTIVE, HIGH-STRENGTH ZIRCONIA CERAMICS |
| JPS57140376A (en) | 1981-02-20 | 1982-08-30 | Ngk Spark Plug Co | Partially stabilized zirconium oxide sintered body for oxygen sensor and manufacture |
-
1983
- 1983-11-17 DE DE19833341524 patent/DE3341524A1/en active Granted
-
1984
- 1984-11-06 NL NL8403374A patent/NL8403374A/en not_active Application Discontinuation
- 1984-11-14 JP JP59238734A patent/JPS60118669A/en active Granted
- 1984-11-15 IL IL73525A patent/IL73525A/en not_active IP Right Cessation
- 1984-11-16 GB GB08429023A patent/GB2149773B/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4835123A (en) * | 1986-02-03 | 1989-05-30 | Didier-Werke Ag | Magnesia partially-stabilized zirconia |
| US4961835A (en) * | 1987-10-20 | 1990-10-09 | Murata Manufacturing Co., Ltd. | Solid electrolyte, sensor therewith and method of making said sensor |
| EP1118601A1 (en) * | 1998-06-22 | 2001-07-25 | Showa Denko Kabushiki Kaisha | Refractory for casting rare earth alloy and method for producing the same and method for casting rare earth alloy |
| EP1118601A4 (en) * | 1998-06-22 | 2005-01-26 | Showa Denko Kk | Refractory for casting rare earth alloy and method for producing the same and method for casting rare earth alloy |
| EP1659102A1 (en) * | 1998-06-22 | 2006-05-24 | Showa Denko Kabushiki Kaisha | Refractory material for casting a rare-earth alloy and its production method as well as method for casting the rare-earth alloys |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0529625B2 (en) | 1993-05-06 |
| NL8403374A (en) | 1985-06-17 |
| GB8429023D0 (en) | 1984-12-27 |
| IL73525A0 (en) | 1985-02-28 |
| GB2149773B (en) | 1987-02-04 |
| DE3341524C2 (en) | 1989-08-31 |
| JPS60118669A (en) | 1985-06-26 |
| IL73525A (en) | 1988-05-31 |
| DE3341524A1 (en) | 1985-05-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20031116 |